Deep-Drawn Piston Accumulator for Low-Inertia Hydraulic Storage

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Solution Overview

Problem

Hydraulic accumulators require efficient and cost-effective production methods to meet the demand for various applications while maintaining favorable operating behavior, particularly in terms of low mass inertia and material costs.

Innovation Solution

The piston part is designed as a deep-drawn part with a tolerance sleeve and O-ring seal, allowing for efficient manufacturing and low material costs, and is divided into a guide and dome-like trough parts to maximize gas volume, with groove-like indentations for sealing and guidance, enabling non-tilting guidance and reduced mass inertia. The piston part can be made from fine-grain sheet metal or AlMg alloy, and the accumulator housing can be produced without complex internal machining, using composite materials for lightweight designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the piston part is manufactured using traditional machining methods, then manufacturing precision can be achieved, but production costs increase and production efficiency decreases

Engineering Contradiction:
Improveproduction costVSAvoidpiston dimensional accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces traditional mechanical machining processes with deep-drawing technology to manufacture the piston part. This substitution eliminates complex cutting operations, reduces tooling requirements, and enables more efficient production while maintaining acceptable dimensional tolerances through the inherent precision of the deep-drawing process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the manufacturing approach from subtractive machining to formative deep-drawing, fundamentally altering the production parameters. This includes changing the material form (from blank to drawn shape), the manufacturing process type, and the resulting geometric characteristics, all of which contribute to reduced costs and improved efficiency

Inventive Principle:
Principle #35Parameter changes

2Strength

If the piston part is made as a solid structure, then strength is improved, but mass inertia increases and operating behavior deteriorates

Engineering Contradiction:
Improvepiston structural strengthVSAvoidpiston mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent employs a thin-walled hollow piston structure instead of a solid piston. This shell-like construction significantly reduces the mass of the moving piston while maintaining sufficient structural strength through the hollow geometry and material selection, thereby improving operating behavior and reducing mass inertia

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention specifies the use of aluminum or aluminum alloy materials for the piston part. These materials provide an optimal balance between strength and weight, enabling the thin-walled hollow structure to achieve the required mechanical properties while minimizing mass for improved dynamic performance

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If the accumulator housing is designed with complex internal machining for piston guidance, then guidance precision is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvepiston guidance precisionVSAvoidhousing structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the piston guidance function from the accumulator housing itself and relocates it to a separate running tube component. This separation eliminates the need for complex internal machining of the housing, simplifies the housing structure, and allows the guidance function to be implemented in a dedicated component that can be manufactured more simply

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the accumulator system into distinct functional components: the housing, the running tube (for guidance), and the piston. This segmentation allows each component to be optimized and manufactured independently, reducing the overall manufacturing complexity while maintaining guidance precision through the specialized running tube

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3289227B1Hydraulic accumulator
Publication Date: 2021.09.29 HYDAC TECH GMBH
  • EP3289227B1 patent drawingFigure 1~2
  • EP3289227B1 patent drawingFigure 3
  • EP3289227B1 patent drawingFigure 4

AI summary

The invention relates to a hydraulic accumulator, especially a piston accumulator, in which a piston part (27) separates from each other two media spaces (23, 25) inside a storage housing (1), characterized in that the piston part (27) is designed as a deep-drawn part.